refactor: cleanup BeadSort

[alxkm]

Cleanup BeadSort and BeadSortTest, adding javadocs.

• I have read CONTRIBUTING.md.
• This pull request is all my own work -- I have not plagiarized it.
• All filenames are in PascalCase.
• All functions and variable names follow Java naming conventions.
• All new algorithms have a URL in their comments that points to Wikipedia or other similar explanations.
• All new code is formatted with clang-format -i --style=file path/to/your/file.java

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 40.08%. Comparing base (208e1e9) to head (a8a7392).

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #5269      +/-   ##
============================================
+ Coverage     40.07%   40.08%   +0.01%     
- Complexity     2464     2468       +4     
============================================
  Files           519      519              
  Lines         15479    15484       +5     
  Branches       2954     2952       -2     
============================================
+ Hits           6203     6207       +4     
- Misses         8986     8987       +1     
  Partials        290      290              

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